Sample/Serial comms Noise

[neonascent]

Hi Ole - I love the project, and really appreciate your time putting it all up!

I'm having some issues with noise from the system. It's all harmonics of 60Hz, and I can't tell if it's electrical noise from the serial send every second, or possibly a sampling artifact?

It gets a bit less noisy if I use 12v power for the Arduino; maybe my capacitor choices are incorrect?

Any suggestions would be appreciated

[neonascent]

Ah I have realized I have put an LED where there should be an inductor! But what value of inductor? It's not labelled on Schematic or PCB file.

[olewolf]

The inductor is just a coil intended to suppress noise. I'm relatively sure you omit the inductor (that is, just short it) so you can use JP3 to select 5V or 3.3V.

[neonascent]

Thank Ole - I'd love to take advantage of a coil to suppress some noise, but I don't know what a good value would be. What inductance / Henries value would you suggest?